The present invention relates to a load sharing control method for controlling load sharing in a parallel computer system, and particularly to an effective technique to be applied to a load sharing control method for sharing a multiple of kinds of jobs or sessions among a plurality of computers in a parallel computer system with good balance to improve processing speed and guarantee of the turn-around time of jobs.
As main jobs or sessions executed in a conventional computer system, there are jobs or sessions performed by batch process, online process and TSS (timesharing system) process. The jobs, sessions or transactions are hereinafter referred to as "works". In order to operate these works efficiently in one computer system, the order of priority for execution of the works is set by parameters
On the other hand, the idea of executing a plurality of works in a parallel computer system having a plurality of computers connected in parallel has been proposed to increase the amount of works to be executed. Upon such a background, some methods or apparatuses have been proposed as load sharing control methods or load sharing control apparatuses each used in a parallel computer system for sharing a load among a plurality of computers executing a plurality of works.
JP-A-3-19035 discloses a job execution multiplicity control system in which the job execution multiplicity of a job execution queue as a whole is adjusted to attain increased speed of a batch job while the computer system is in operation.
In brief, the job execution multiplicity control system comprises a number-of-jobs recognition means for recognizing the number of currently running jobs from the job execution queue as a whole, a job execution multiplicity recognition means for making the computer system recognize designated job execution multiplicity, and a job control means for controlling job extraction.
JP-A-5-197682 discloses an online job dynamic load control system in which the lowering of online response can be prevented effectively even in the case where dynamic load in online transaction increases.
In brief, the dynamic load control system comprises a load state recognition means for measuring load on a central computer at predetermined timing to recognize the state of load, and a starting control means for changing/controlling the processing multiplicity of sessions to be executed only when the measured value of load exceeds a predetermined value.
Further, JP-A-3-257654 discloses a load sharing system using session multiplicity in which sessions re assigned to processors in a range of session largest multiplicity to thereby reduce an overhead of a load sharing process per se to improve efficiency of a computer system as a whole.
In brief, when the number of currently operating sessions on a multiplicity information table for storing the session largest multiplicity and the number of currently operating sessions correspondingly to the respective processors does not exceed the largest multiplicity, a session requested to be started is assigned to and started by one of the processors which is determined correspondingly to the session largest multiplicity
Further, JP-A-6-19861 (U.S. Pat. No. 5,504,894) discloses a transaction processing server path setting mechanism in which response time of online transaction is set by a user by the job class so that the transaction is shared to achieve the response time.
In brief, in a multiprocessor transaction processing system, a transaction is classified into a plurality of classes in accordance with the processing time required therefor, target response time is set by the class and load on each transaction processing server is adjusted so that response performance becomes best in relation between the target response time and actual processing time with respect to all the classes.
As a result of study of the aforementioned prior art references, the present inventors have found the following problems.
That is, in the load sharing control method disclosed in the first-mentioned prior art reference, the load sharing control method is carried out in only one utilization mode in which one kind of works are executed. Accordingly, there is a problem that load sharing adapted to other utilization modes in which a plurality of kinds of works are executed by batch process, online process, TSS process, etc. cannot be carried out.
Further, in the load sharing control method according to the aforementioned prior art, in order to make it possible to share load in accordance with the utilization mode for executing a plurality of kinds of works, load sharing in accordance with an operation mode is carried out in a manner so that the number of initiators (the number of sessions), which indicates multiplicity and which is defined in each sub-system for executing a specific one kind of works is set so as to be different from the number of initiators in another sub-system
It is however required that a plurality of sub-systems for executing a specific kind of work processes are required to take charge of other kinds of works correspondingly to the characteristic thereof to hereby attain the increase in processing speed.